Pre-filter or shroud with helical stepped wall

ABSTRACT

A vacuum cleaner includes a body. A suction generator and a dirt collection vessel are both carried on the body. The dirt collection vessel includes an arcuate side wall, a tangentially directed inlet, an axially directed outlet, a dirt collection chamber and a shroud provided between the dirt collection chamber and the axially directed outlet. The shroud includes a filter surface having a plurality of air flow apertures and a helical step extending around the shroud through the filter surface.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

The present invention relates generally to the floor care appliance field and, more particularly, to a vacuum cleaner incorporating a dirt collection vessel with novel structure for providing enhanced cleaning efficiency.

BACKGROUND OF THE INVENTION

Floor cleaning appliances with cyclone cleaning action are well known in the art. For example, many upright vacuum cleaners and canister vacuum cleaners incorporate one or more cyclones in order to enhance cleaning efficiency. Disclosed herein is a new and improved dirt collection vessel incorporating a novel and unobvious structure to enhance the cyclonic action and cleaning efficiency of the dirt collection vessel and the vacuum cleaner or other cleaning appliance into which the dirt collection vessel is incorporated.

SUMMARY OF THE INVENTION

A vacuum cleaner comprises a body, a suction generator and a dirt collection vessel. The suction generator and dirt collection vessel are both carried on the body. The dirt collection vessel includes an arcuate sidewall, a tangentially directed inlet, an axially directed outlet, a dirt collection chamber and a shroud provided between the dirt collection chamber and the axially directed outlet. The shroud includes a filter surface having a plurality of air flow apertures and a helical step extending around the shroud through the filter surface.

More specifically, the shroud includes a lip and a skirt. The filter surface and the helical step extend between the lip and skirt. In one possible embodiment the helical step has a width of between about 10 and about 16 mm and a length of between about 210 and about 250 mm. Further, the helical step extends through an arc of between about 180 and about 270 degrees around the shroud.

The helical step engages the lip adjacent the tangentially directed inlet. The skirt includes a hollow adjacent a point where the helical step meets the skirt. The hollow includes an air flow guide wall that diverges from the helical step. Further, the skirt and the arcuate sidewall define a continuous gap having a width of between about 9 and about 13 mm. Further, the plurality of airflow apertures each have a diameter of between about 25 and about 26 mm and define a total surface area of between about 900 mm² and about 1400 mm².

A first portion of the filter surface is on a first side of the helical step while a second portion of the filter surface remains unrecessed on a second side of the helical step. Between about 25 and about 40 percent of the plurality of air flow apertures are provided on the first portion and between about 60 and about 75 percent of the plurality of air flow apertures are provided on the second portion.

In the following description there is shown and described a vacuum cleaner and a dirt collection vessel, simply by way of illustration of one possible embodiment of the devices. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated herein and forming a part of the specification, illustrate several aspects of the vacuum cleaner and dirt collection vessel and together with the description serve to explain certain principles of the devices. In the drawings:

FIG. 1 is a front plan view of one possible embodiment of a vacuum cleaner;

FIG. 2 is a left side elevational view of the vacuum cleaner illustrated in FIG. 1;

FIG. 3 is a rear elevational view of the same vacuum cleaner;

FIG. 4 is an exploded perspective view of the dirt collection vessel of the vacuum cleaner;

FIG. 5 is a partially broken away view of the assembled dirt collection vessel;

FIG. 6 is a cross sectional view of the assembled dirt collection vessel; and

FIGS. 7 and 8 are perspective views of the shroud of the dirt collection vessel at different angular orientations so as to clearly illustrate the helical step which extends around the shroud and through the filter surface and the hollow formed in the skirt of the shroud.

Reference will now be made in detail to the present preferred embodiment of the invention, examples of which are illustrated in the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Reference is now made to drawing FIGS. 1-3 illustrating an upright vacuum cleaner 10. The upright vacuum cleaner 10 is just one possible embodiment of the present invention. Other embodiments include but are not limited to canister vacuum cleaners. The upright vacuum cleaner 10 includes a body 12 comprising a nozzle assembly 14 and a handle assembly 16. The handle assembly 16 is pivotally connected to the nozzle assembly 14 and may be used to guide the vacuum cleaner 10 to and fro across the floor during the cleaning operation in a manner well known in the art.

The nozzle assembly 14 includes a housing 18 forming an agitator cavity 20 that receives a rotary agitator 22. The rotary agitator 22 includes bristle tufts 24 or other resilient projections. As the agitator 22 is rotated, the bristle tufts 24 beat dirt and debris from the nap of an underlying carpet or rug being cleaned.

The handle assembly 16 includes a control stalk 26 carrying a hand grip 28. A dirt collection vessel, generally designated by reference numeral 30, is also carried on the handle assembly 16 adjacent the control stalk 26. The dirt collection vessel 30 will be described in greater detail below.

A suction generator 32 is also carried on the body 12. In the illustrated embodiment, the suction generator 32 is carried within the lower housing 34 of the handle assembly 16. The lower housing 34 also carries a cord reel 36 having an electrical cord and plug 38 adapted for mating attachment with a standard electrical wall outlet. Power is provided to the vacuum cleaner 10 through the plug 38 and associated electrical cord. In an alternative embodiment, not illustrated, the vacuum cleaner 10 may be powered by batteries.

As should be appreciated, the vacuum cleaner 10 rolls smoothly across the floor on ground engaging wheels 40 (see particularly FIG. 2).

During operation, the suction generator 32 draws an air stream through the agitator cavity 20 into the vacuum cleaner 10. Dirt and debris loosened by the rotary agitator 22 are entrained in this air stream and directed serially through the suction inlet in the nozzle assembly, the conduit 42, the flexible hose 44 and the fitting 46 into the tangentially directed inlet 48 of the dirt collection vessel 30 (see also FIGS. 4 and 5).

Dirt and debris are captured in the dirt collection vessel 30 in a manner that will be described in greater detail below. Relatively clean air discharged from the dirt collection vessel 30 passes over the motor of the suction generator 32 to provide cooling. That air stream then passes through a final filter (not shown), then over the cord reel 36 to provide cooling before being exhausted through vents 50 back into the environment.

Reference is now made to FIGS. 4-6 which provide detailed illustrations of the dirt collection vessel 30. As illustrated, the dirt collection vessel 30 includes a dirt cup 52 having a stepped arcuate sidewall or substantially cylindrical outer wall 54. The tangentially directed air inlet 48 is provided in this outer wall 54. The dirt cup 52 also includes a bottom wall 56 that is connected to the sidewall 54 via a hinge 58 and a latch 60. A seal 62 ensures an air tight connection between the bottom wall 56 and the side wall 54. As will be described in greater detail later, the dirt cup 52 functions as both the primary cyclone and primary cyclone dirt collection chamber of the dirt collection vessel 30.

The dirt collection vessel 30 also includes a secondary cyclone assembly, generally designated by reference numeral 64. The secondary cyclone assembly includes the support element 66, the support ring 68, a plurality of secondary cyclones 70 (eight are illustrated in the drawing figure although substantially any number between one and twenty could be provided) and a secondary cyclone assembly housing 72. As best illustrated in FIGS. 4-6, the support element 66 is concentrically received within the sidewall 54 of the dirt cup 52. The end 74 of the support element 66 is received in a groove 76 formed in the bottom wall 56. A seal 78 provided in the groove 76 between the bottom wall 56 and the end 74 of the support element 66 completes an air tight connection. The support ring 68 is received in the funnel shaped upper end 80 of the support element 66 where it rests on the shoulder 82.

As best illustrated in FIG. 4, the support ring 68 includes a series of eight circular openings 84 that receive the discharge ends of the secondary cyclones 70. The bases 86 of the secondary cyclones 70 seat on the top of the dirt cup 52 with the seal 88 completing the air tight connection. The upper housing 72 seats on the base 86 over the cyclones 70. The housing 72 includes a series of eight discharge outlets 90. One discharge outlet 90 is axially aligned with each of the secondary cyclones 70.

The top 92 of the dirt collection vessel 30 comprises an exhaust manifold 94 having a discharge outlet 96. The exhaust manifold 94 also includes a filter support 98 which holds a filter 100. Further, the top 92 includes a spring loaded latch mechanism 102 for securing the dirt collection vessel to the control stalk 26 of the handle assembly 16 and a handle cover 104.

A shroud 106 is concentrically received between the support element 66 and the side wall 54 of the dirt cup 52 (see FIGS. 4-6). The shroud 106 includes a lip 108, a skirt 110 and a filter surface 112 which extends between the first and skirts. The filter surface 112 includes a plurality of air flow apertures 114. In addition the shroud 106 includes a helical step 116 that extends around the shroud through the filter surface 112 between the lip 108 and skirt 110.

In one particularly useful embodiment the helical step has a width of between about 10 mm and about 16 mm and a length of between about 210 mm and about 250 mm. Further, the helical step 116 extends through an arc of between about 180 and about 270 degrees around the circumference of the filter surface 112. As best illustrated in FIG. 5, when the dirt collection vessel 30 is completely and properly assembled, the helical step 116 engages the lip 108 adjacent the tangentially directed inlet 48. In this position, the helical step 116 is ideally oriented to direct the air stream coming from the inlet downwardly toward the bottom wall 56 of the dirt cup 52.

As best illustrated in FIG. 8, the skirt 110 includes a hollow 140 adjacent the point where the helical step 116 meets the skirt. The hollow 140 is aligned with the helical step 116 and includes an airflow guide wall 142. The air flow guide wall 142 and helical step 116 form an included angle of between about 38 and about 48 degrees. In one particular embodiment, the included angle is about 43 degrees.

It should be appreciated that air flowing along the helical step 116 is directed into and through the hollow 142 in the skirt 110. The diverging nature of the guide wall 142 produces a transition for the air flowing along the helical step 116 to pass the diameter of the skirt 110 which helps to direct the dirt particulates thereby increasing the cleaning efficiency of the vacuum cleaner 10. In an alternative embodiment illustrated in FIG. 4, the hollow 140 and guide wall 142 are eliminated and a gap 150 is provided in the skirt 110 instead. The gap 150 allows for air to flow freely off the helical step 116.

The air stream passes through the continuous gap 118 defined between the arcuate sidewall 54 and the outer edge of the skirt 110. Here it is also significant to note that the step 120 in the sidewall 54 is provided adjacent to the skirt 110. Typically, the circumference of the sidewall 54 above the step 120 is between about 120 mm and about 135 mm while the circumference of the sidewall 54 below the step 120 is between about 140 mm and about 155 mm. Typically, the step increases the circumference of the sidewall between about 15 mm and about 25 mm.

The plurality of airflow apertures 114 each have a diameter of between about 25 and about 26 mm and define a total surface area of between about 900 mm² and about 1400 mm². Further, it should be appreciated that a first portion 122 of the filter surface 112 is provided on a first side of the helical step 116 while a second portion 124 of the filter surface is provided on a second side of the helical step. That second portion 124 of the filter surface remains un-recessed and is on the projecting side of the filter surface/helical step. Between about 25 and about 40 percent of the plurality of air flow apertures 114 are provided on the first or recessed portion 122 of the filter surface 112 whereas between about 60 and about 75 percent of the plurality of air flow apertures are provided on the second or recessed portion 124 of the filter surface (see particularly FIGS. 7 and 8).

During vacuum cleaner operation the dirty air stream from the nozzle assembly 14 passes through the conduit 42, the flexible hose 44 and the fitting 46 to the tangentially directed inlet 48. The air stream travels through the tangentially directed inlet 48 into the dirt cup 52 where it rapidly flows in cyclonic fashion around the interior of the sidewall 54. Advantageously, the helical step 116 provided on the shroud 106 functions to influence the air stream in a downward direction through the hollow 140 toward the bottom wall 56. As the cyclonic air stream flows downwardly it passes through the gap past the skirt 110 and step 120 into the lower portion of the dirt cup with the larger circumference. This causes a slight reduction in the speed of the air flow so that the relatively large particles of dirt and debris traveling along the side wall 54 tend to quickly drop toward the bottom of the dirt cup where they collect along the bottom wall 56.

The relatively clean air, minus the larger particles of dirt and debris is then gradually drawn inwardly toward the shroud 106. The relatively clean air passes through the air flow apertures 114 and then moves through the axial outlet 126 of the primary cyclone. The air stream then passes around outside of the secondary cyclones 70 and is directed by the air guide 128 into the tangentially directed inlets 130 of each individual secondary cyclone 70. The air stream then moves in cyclonic fashion through the parallel secondary cyclones 70. Relatively fine particles of dirt and debris that remain in the air stream move along the interior side walls of the secondary cyclones 70, slow through friction with those side walls and drop downwardly through the particle discharge openings 132 of the secondary cyclones 70 into the funnel shaped open end 80 of the support element 66. The particles then drop into the fine dust particle collection chamber 134 formed by the support element 66 and that portion of the bottom wall 56 inside the grooves 76. Clean air passes from each of the secondary cyclones 70 through the axially directed outlet 136. Each axially directed outlet 136 is aligned with one of the discharge outlets 90 in the housing 72. Thus, the air stream passes through the discharge outlets 90 and then the filter 100 into the manifold 94. Next the air stream passes through the discharge outlet 96 and downwardly through the control stalk 26 to the lower housing 34 of the handle assembly. The air stream then flows over the motor of the suction generator 32 to provide cooling. Next, the air stream flows through a final filtration filter such as a HEPA filter before passing over the cord reel 36 to provide cooling to the cord reel on its way to being exhausted back into the environment through the exhaust vents 50.

The foregoing description of preferred embodiments have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the vacuum cleaner to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments were chosen and described to provide the best illustration of the principles of the vacuum cleaner and its practical application to thereby enable one of ordinary skill in the art to utilize the vacuum cleaner in various embodiments and with various modifications as are suited to the particular use contemplated. The drawings and preferred embodiments do not and are not intended to limit the ordinary meaning of the claims in their fair and broad interpretation in any way. 

What is claimed:
 1. A vacuum cleaner, comprising: a body; a suction generator carried on said body; and a dirt collection vessel carried on said body, said dirt collection vessel including an arcuate sidewall, a tangentially directed inlet, an axially directed outlet, a dirt collection chamber and a shroud provided between said dirt collection chamber and said axially directed outlet; said shroud including a filter surface having a plurality of air flow apertures and a helical step extending around said shroud through said filter surface.
 2. The vacuum cleaner of claim 1, wherein said shroud includes a lip and a skirt and said filter surface and said helical step extend between said lip and skirt.
 3. The vacuum cleaner of claim 2, wherein said helical step has a width of between about 10 and about 16 mm.
 4. The vacuum cleaner of claim 3 wherein said helical step has a length of between about 210 and about 250 mm.
 5. The vacuum cleaner of claim 4, wherein said helical step extends through an arc of between about 180 and about 270 degrees.
 6. The vacuum cleaner of claim 5, wherein said helical step engages said lip adjacent said tangentially directed inlet.
 7. The vacuum cleaner of claim 6, wherein said skirt and said arcuate sidewall define a continuous gap having a width of between about 9 and about 13 mm.
 8. The vacuum cleaner of claim 1, wherein said helical step has a width of between about 10 and about 16 mm.
 9. The vacuum cleaner of claim 8, wherein said helical step has a length of between about 210 and about
 250. 10. The vacuum cleaner of claim 9, wherein said helical step extends through an arc of between about 180 and about 270 degrees.
 11. The vacuum cleaner of claim 1, wherein said plurality of air flow apertures each have a diameter of between about 25 and about 26 mm and define a total surface area of between about 900 mm² and about 1400 mm².
 12. The vacuum cleaner of claim 1, wherein a first portion of said filter surface is on a first side of said helical step and a second portion of said filter surface remains unrecessed on a second side of said helical step.
 13. The vacuum cleaner of claim 12, wherein between about 25 and about 40 percent of said plurality of airflow apertures are provided on said first portion and between about 60 and about 75 percent of said plurality of airflow apertures are provided on said second portion.
 14. The vacuum cleaner of claim 2, wherein said skirt includes a hollow adjacent a point where said helical step meets said skirt.
 15. The vacuum cleaner of claim 14, wherein said hollow includes an air flow guide wall diverging from said helical step.
 16. The vacuum cleaner of claim 15, wherein said air flow guide wall and said helical step define an included angle of between about 38 and about 48 degrees.
 17. The vacuum cleaner of claim 15, wherein said air flow guide wall and said helical step define an included angle of about 43 degrees.
 18. The vacuum cleaner of claim 2, wherein said arcuate sidewall includes a step provided adjacent said skirt.
 19. The vacuum cleaner of claim 18, wherein said arcuate sidewall has a circumference of between about 120 mm and about 135 mm on a first side of said step and a circumference of between about 140 mm and about 150 mm on a second side of said step.
 20. The vacuum cleaner of claim 2, wherein said skirt includes a gap adjacent a point where said helical step meets said skirt. 